From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4D3E5169.8050103@domain.hid> Date: Tue, 25 Jan 2011 05:28:25 +0100 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <4D3E385A.5010209@domain.hid> <4D3E42BA.4000601@domain.hid> <4D3E4EBA.6050806@domain.hid> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] Segmentation Fault when writing in registers (AT91SAM - ARM9) List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: at91_enthus Cc: xenomai-help at91_enthus wrote: > On Mon, Jan 24, 2011 at 10:16 PM, Gilles Chanteperdrix < > gilles.chanteperdrix@xenomai.org> wrote: > >> at91_enthus wrote: >>> On Mon, Jan 24, 2011 at 9:25 PM, Gilles Chanteperdrix < >>> gilles.chanteperdrix@xenomai.org> wrote: >>> >>>> at91_enthus wrote: >>>>> On Mon, Jan 24, 2011 at 8:41 PM, Gilles Chanteperdrix < >>>>> gilles.chanteperdrix@xenomai.org> wrote: >>>>> >>>>>> at91_enthus wrote: >>>>>>> Hi. >>>>>>> >>>>>>> I was testing Xenomai on my AT91SAM9G20-based board and tried to >> adapt >>>>>> the >>>>>>> code found here: >>>>>>> http://www.armadeus.com/wiki/index.php?title=Xenomai:Blinking_LEDs . >>>>>> By the way, this code is ridiculous. It creates a real-time task to >>>>>> write to some non real-time device, which makes the real-time task >>>> useless. >>>>> I know. >>>> Yes, but this example is bad in many ways: >>>> - first it uses xenomai api to create a real-time task, and uses write >>>> which causes the real-time task to switch to secondary domain; >>>> - the Makefile does not use xeno-config, which have been the recommended >>>> way of getting the compiler flags since day 1; >>>> - it nullifies SIGTERM and SIGINT, which is a dubious decision, and >>>> could lead people to believe that they should do the same when using >>>> Xenomai, whereas there is no such requirement. >>>> - the pointers point to outdated version of the documentation. >>>> - it uses runinfo/xeno-load, which are kind of outdated too, make things >>>> uselessly complicated, and in any case, tell you to type Ctrl-C to >>>> interrupt the program, which is bound to fail if anything goes wrong, >>>> since SIGINT is neutralized in the program. >>>> >>>>> That's why I went to mmap(). >>>> That is not really the right solution either. I admit that for driving >>>> leds, it may be a bit overkill, but anyway, what you should do is write >>>> an RTDM driver for driving the leds. Keeping the driver separated from >>>> the application will allow the same program to run on other platforms >>>> where driving the LEDS is done differently without changing much of the >>>> application code. In other word, the application/driver separation is a >>>> sane one. >>>> >>>> Anyway, mmap should work. >>>> >>>> (I chose that sample code because, for >>>>> now, I am only learning to use basic functions) >>>>>> Wrong test here. Should be "if (aic_base == MAP_FAILED)" >>>>> Indeed, my program fails miserably when I check the mapping of AIC, not >>>>> PIOB's. And yet, I just can't figure why in the non-Xenomai code, AIC >>>>> mmap-ing works fine. >>>> Well errno might give you a clue. Do you have FCSE enabled? >>>> >>>> Regards. >>>> >>>> -- >>>> Gilles. >>>> >>> FCSE is enabled. errno returns 22 (invalid argument). >> best effort or guaranteed? > > > Best effort > > >> Please activate FCSE messages. > > > ... compiling new kernel > > >> How big is >> MAP_SIZE? >> >> > 4096 Ok. Could you post your full kernel configuration, as well as the full program? Are you running this program as root? -- Gilles.